The present invention relates to a vehicle control system. More specifically the present invention relates to an electric motor, actuator, or other control device in an automobile having integral control circuitry.
An area in the auto industry seeing tremendous change from past practices is the area of wiring and interconnects. The creation of relatively inexpensive microprocessors, the reduction in size of power components, and the digital revolution have put the power of the computer age into the hands of automotive engineers. Traditionally large bundles of wires were used to conventionally connect electrical devices in automobiles, each wire representing a single switching signal or analog value. These bundles of wires increased the weight, volume, and complexity of the car. With the development of small relatively inexpensive power transistors and the advent of automotive computer networks such as the controller area network (hereinafter xe2x80x9cCANxe2x80x9d) and SAE J1850, many of these wires and their associated terminations and connectors can be eliminated. Large amounts of information can now be transferred between intelligent control devices in an automobile via a single wire.
In conventional driven applications utilizing an electric motor, numerous components such as drives, controllers, and wiring connections are needed. The motor of choice in most automotive applications, because of its simple construction and the readily available direct current (hereinafter xe2x80x9cDCxe2x80x9d) power from a vehicle battery and alternator, is a DC motor. A DC motor normally comprises a rotating armature and energized field. The rotating armature is usually mechanically commutated with brushes and the energized field is normally created by permanent magnets (although field windings may be used). The speed of the DC motor is related to the applied armature voltage and the torque is related to the applied armature current and field strength. The direction of a DC motor may be changed by merely changing the direction of the motor current in the armature winding(s).
In the past, to control an electrical motor, such as the previously described DC motor, a remote drive or controller would receive power, movement instructions, and sensor signals from the electrical system of a vehicle through numerous wires and connections. The remote controller would further transfer power to an electrical motor and receive feedback from the electrical motor through even more wires and connections. For example, the power relay used with a simple bi-directional DC motor system to switch the direction of the current and thus the rotation of a DC motor would normally be located on the remote controller. A high power connection would have to be made from the automobile electrical system to the remote controller and also from the remote controller to the electrical motor. These high power connections on the remote controller necessitate increased size for connectors on the remote controller and thus an overall increase in size and complexity for the remote controller. Similarly, feedback and control signals, including position, current, and speed from the motor would require additional wiring from the motor to the remote controller. The complexity of such an electrical assembly can lead to wiring errors, improper operation, and require relatively large spaces to incorporate the large wiring bundles. The present invention seeks to eliminate these problems.
The present invention incorporates control circuitry on a printed circuit board (hereinafter xe2x80x9cPCBxe2x80x9d) coupled to or within a housing for a motor, actuator, or other similar control device to create a unitary apparatus for automotive applications. The control circuitry adds intelligence to the control device and allows it to localize control loops, feedback information, and other signals or actions. Only a single communication connection is needed to receive and transmit control instructions to and from the central control system of an automobile. The incorporation of the control circuitry and housing into a single unit eliminates the large bundles of wires normally used to transfer control signals, replacing them with a single communication wire and power connection.
Moving power components such as high current switching to a motor housing allows remote controllers to become low current devices, reducing the size of the remote controllers and their intricacy. Integrating sensors and other instrumentation with a motor improves the performance of the system and it modularity. The motors of the present invention have integrated current sensing, over current trip, diagnostics, position sensing, and motor speed and direction control. Control and sensor information to and from the motor is transferred by serial bus to the remote controller which is further linked to the central control system in an automobile by another communication system such as CAN or SAE J1850. Thus all control signals may be easily transferred to and from the operator through a simple network of communication wires and not through a bundle of individual control signal wires as done in the past.
The open architecture of the remote controller allows for the addition of more motors or other features such as heat seating or lumbar support movement and massage, without effecting the structure of the basic system. The serial bus from the remote controller may be expanded to include multiple nodes by simply extending the serial wiring Thus by putting intelligence on a motor or other actuation device numerous control wires are eliminated. This is beneficial in the design and engineering of automobile electrical systems due to the limited space available for wire harnesses and electrical connectors.